The Autoclave Knowledge Bank your impartial guide to autoclave selection

Introduction When specifying or purchasing an expensive and complicated piece of equipment it is essential to be able to ask the right questions in order to get the right answers and make an informed decision. This booklet will guide you through some of the key points to consider before making that all important laboratory autoclave purchase. It is important to think about what you are going to put into the autoclave to make sure that the autoclave you buy has the best specification to process it effectively and efficiently, especially if you are going to have to prove this to a certifying body...

Surely steam sterilisers are all the same 5 Front loading autoclaves 9 Pass through autoclaves 10 How will steam be generated 17 Hygiene and environmental issues 31 Recording keeping and proving sterilisation 32 Other things to consider 35

What is an Autoclave? An autoclave (from Greek auto-, ultimately meaning self, and Latin clavis meaning key—a self-locking device) is defined as “a strong heated container used for chemical reactions and other processes using high pressures and temperatures”. As the definition would suggest, there are many types of autoclave available for a wide variety of purposes. In the chemical industry they can be used to cure coatings, vulcanize rubber and for hydrothermal synthesis like growing crystals under high temperatures and pressures - synthetic quartz crystals used in the electronic industry are...

Surely steam sterilisers are all the same? They are not. Even within the group of autoclaves used for steam sterilisation there are a range of types. Broadly these fall into three different types, all capable of steam sterilisation but manufactured to give the best performance for the type of operation for which they have been designed. Firstly there are small table top instrument sterilisers commonly seen in Dentist and Doctor’s surgeries. These are designed to give fast and reliable sterilisation of small batches of surgical instruments usually with one or two fixed cycles. contact with patients...

Autoclave Types Since most manufacturers produce a range of laboratory autoclave types to meet many differing requirements it is important to understand initially your laboratory’s requirements in terms of load variation and frequency of sterilising applications. What is the most appropriate in terms of available lab space, would a benchtop suffice or a larger capacity free-standing, top or front loading autoclave be a better option? porous loads can also be processed. All are critical in the maintenance of good hygiene practice and sterile working conditions. The images below are examples of...

Autoclave Type continued from page 6 suited to applications and available financial budget. Broadly the range of autoclaves available are: Benchtop Top loading Front loading Pass-through These will also be available with a range of door types, chamber configurations and heating methods. Each offers unique benefits. Benchtop Autoclaves If you operate a small laboratory with limited floor space, items for sterilisation are relatively small and throughput is infrequent then a Benchtop Autoclave could be the most appropriate choice. As the name implies this type of autoclave is designed specifically...

Top Loading Autoclaves This is a really practical choice for those laboratories with limited space yet wanting to perform high-quality steam sterilisation of taller than normal items such as fermentors and large capacity Erlenmeyer flasks and where space and budgets are restricted. The alternate may require a much larger and more expensive front-loading autoclave. The main advantage, which is attractive to the smaller laboratory or those with low throughput is the actual ‘footprint’ of the autoclave - not requiring much additional width and depth outside that of the chamber space. Top loading...

Front Loading Autoclaves This style of laboratory autoclave is available from some manufacturers with a choice of round or rectangular sterilising chambers. These have the advantage over top loading models, they are easier to load but they take up a larger floor space. However some manufacturer’s models take up less floor space for the same chamber capacity than others so if laboratory space is a big issue then it is worth comparing different manufacturers for the most compact models. Due to the increased volume of medium that can be processed in a single pass, especially in larger models, consideration...

Pass Through Autoclaves Every lab is unique in what processes and procedures take place – some requiring a more sterile working environment than others, there may even be air locks for staff to pass through, extracting, cleansing and renewing the air, a system in operation where high risk conditions are the norm. If your requirement is for a clean room application the autoclave is used for the sterilisation of equipment entering a clean or aseptic area such as a pharmaceutical production environment. In a similar manner, some laboratories need to have a secure, clean exit path for its waste media...

Pass Through Autoclaves continued from page 10 standard product design, effectively placing two units back-to-back but with a single chamber which is open both ends to allow for doors at either end. All pass-through systems require safety interlocks to be fitted so that the integrity of the clean room or containment area is not compromised by both doors being opened at the same time. Generally the autoclave is set up for loads to pass through in one direction but some manufacturers can offer systems where the direction of flow can be securely reversed or even so that the autoclave can be used...

Chamber Style - Round or Rectangular? Most sterilising chambers are manufactured in stainless steel and are available in a choice of two formats – round or rectangular. Round, also known as cylindrical chambers, are the most common style of chamber since they are available in both front loading and top loading autoclaves. If your application requires sterilising a variety of medium, in small or tall packages, this is a worthwhile design to consider. A cylindrical chamber normally has thinner walls and therefore less metal to heat up which makes processing time faster. Also it weighs less and...